This invention relates generally to light responsive control systems and particularly to a system for identifying kinescope panel types in accordance with the light transmission capability of such panels.
During the production of picture tubes for color television receivers a coating of black matrix material is applied to the inside surface of the panels upon which the viewing screen is produced. The black matrix coating includes a large number of transparent areas which have a particular configuration and which are arranged in a particular pattern, depending upon the type of picture tube being produced. Thus, the transparent areas can be dots, when a dot type of tube is to be produced, or long vertical transparent lines, when a line screen type of tube is to be produced. In either event, the transparent areas are coated with slurries of photosensitive materials including phosphors which emit the three primary colors of light when impacted by electrons. Typically, prior to the application of the phosphors, the widths and other dimensions of the transparent areas are measured to verify that the dimensions of the areas are within acceptable tolerances to avoid the expensive application of phosphors to improperly matrixed panels. A method for measuring the transparent dots in a dot type of panel is described in Application Ser. No. 856,008 filed Apr. 25, 1986, entitled "Method Measuring Transparent Elements In An Opaque Medium" by Frank S. Krufka. A system for measuring the lines and line spacings in line type of kinescope panel is described in U.S. Pat. No. 4,525,735. The teachings of these disclosures are incorporated herein by reference.
Although the referenced application and patent are respectively directed to measuring dots and lines in kinescope panels, both measurements typically are made utilizing a programmable computer. This is advantageous because a single programmable computer can be utilized to effect both measurements. Accordingly, both types of panels can be measured in random order by the system. However, the random measurement of various types of panels requires that the panel type be identified to the computer prior to initiating the measurement routine. Some of the panels have dot shaped transparent areas, and other panels have line shaped transparent areas. Accordingly, the transmission of light through the two types of panels is different. Also, various types of dot screens have different size dots, dependent upon the desired resolution of the visual display. The same is true of line screens, in that screens for larger tubes have larger line widths than those for smaller tubes. The light transmission capabilities of various types of panels, therefore, can be measured and stored. The random processing of various types of panels can be made possible by storing the known transmission capabilities of the various types of panels and comparing the measured transmission capability of an unknown panel type to identify the panel. For these reasons there is a need for a system for identifying kinescope panel types in accordance with the light transmission capabilities of such panels. The present invention fulfills this need.